Collect unclean shutdown debug information

components/browser_watcher/print_report_main_win.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// A utility tool for printing the contents of a stability report encapsulated
+// within a minidump.
+
+#include <windows.h>  // NOLINT
+#include <dbghelp.h>
+
+#include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
+#include "base/strings/stringprintf.h"
+#include "components/browser_watcher/stability_report.pb.h"
+
+namespace {
+
+const char kUsage[] =
+    "Usage: %ls --minidump=<minidump file>\n"
+    "\n"
+    "  Extracts a postmortem stability report from a minidump and prints a \n"
+    "  human readable string.\n";
+
+bool ParseCommandLine(const base::CommandLine* cmd,
+                      base::FilePath* minidump_path) {
+  *minidump_path = cmd->GetSwitchValuePath("minidump");
+  if (minidump_path->empty()) {
+    LOG(ERROR) << "Missing minidump file.\n";
+    LOG(ERROR) << base::StringPrintf(kUsage, cmd->GetProgram().value().c_str());
+    return false;
+  }
+  return true;
+}
+
+void PrintProcessState(FILE* out,
+                       const browser_watcher::ProcessState& process) {
+  fprintf(out, "Process:\n");
+  for (size_t i = 0; i < process.threads_size(); ++i) {
+    const browser_watcher::ThreadState thread = process.threads(i);
+    fprintf(out, thread.thread_name().c_str());
+    fputc('\n', out);
+  }
+}
+
+void PrintReport(FILE* out, const browser_watcher::StabilityReport& report) {
+  for (size_t i = 0; i < report.process_states_size(); ++i) {
+    const browser_watcher::ProcessState process = report.process_states(i);
+    PrintProcessState(out, process);
+  }
+}
+
+int Main(int argc, char** argv) {
+  base::CommandLine::Init(argc, argv);
+
+  // Get the dump.
+  base::FilePath minidump_path;
+  if (!ParseCommandLine(base::CommandLine::ForCurrentProcess(), &minidump_path))
+    return 1;
+
+  // Read the minidump to extract the proto.
+  base::ScopedFILE minidump_file;
+  minidump_file.reset(base::OpenFile(minidump_path, "rb"));
+  CHECK(minidump_file.get());
+
+  // Read the header.
+  MINIDUMP_HEADER header = {};
+  CHECK_EQ(1, fread(&header, sizeof(header), 1, minidump_file.get()));
+  CHECK_EQ(static_cast<ULONG32>(MINIDUMP_SIGNATURE), header.Signature);
+  CHECK_EQ(2U, header.NumberOfStreams);
+  RVA directory_rva = header.StreamDirectoryRva;
+
+  // Read the directory entry for the stability report's stream.
+  // Note: this hardcodes an expectation that the stability report is the first
+  // encountered stream. This is acceptable for a debug tool.
+  MINIDUMP_DIRECTORY directory = {};
+  CHECK_EQ(0, fseek(minidump_file.get(), directory_rva, SEEK_SET));
+  CHECK_EQ(1, fread(&directory, sizeof(directory), 1, minidump_file.get()));
+  CHECK_EQ(static_cast<ULONG32>(0x4B6B0002), directory.StreamType);
+  RVA report_rva = directory.Location.Rva;
+  ULONG32 report_size_bytes = directory.Location.DataSize;
+
+  // Read the serialized stability report.
+  std::string serialized_report;
+  serialized_report.resize(report_size_bytes);
+  CHECK_EQ(0, fseek(minidump_file.get(), report_rva, SEEK_SET));
+  CHECK_EQ(report_size_bytes, fread(&serialized_report.at(0), 1,
+                                    report_size_bytes, minidump_file.get()));
+
+  browser_watcher::StabilityReport report;
+  CHECK(report.ParseFromString(serialized_report));
+
+  // Note: we can't use the usual protocol buffer human readable API due to
+  // the use of optimize_for = LITE_RUNTIME.
+  PrintReport(stdout, report);
+
+  return 0;
+}
+
+}  // namespace
+
+int main(int argc, char** argv) {
+  return Main(argc, argv);
+}